Besides recording transfers of currency, the Bitcoin blockchain is being used to save arbitrary pieces of data.
This can be done by using different techniques, and for different purposes. For instance, a growing number of protocols
embed metadata in the blockchain to certify and transfer the ownership of a variety of assets beyond currency.
A point of debate in the Bitcoin community is whether this unintended use of the blockchain negatively impacts on the
effectiveness of Bitcoin with respect to its primary goal. This project is a systematic analysis of the usage of Bitcoin
metadata over the years. We discuss all the known techniques to embed metadata in the Bitcoin blockchain.
We then extract metadata, and we analyse them to perform several statistics.
In particular, we identify several protocols which embed metadata in the blockchain.